Forsythia cv. `Lemon-Screen`

ABSTRACT

A new cultivar of Forsythia intermedia named `Lemon-Screen` characterized by its vigor, upright fan-shaped habit, lemon yellow flowers, high degree of sterility, its yellow shoots, and light green foliage.

The invention relates to a new cultivar of Forsythia intermedia named "Lemon-Screen", which is characterized especially by its abundance of light yellow flowers, its sterility, yellow stems with chartreuse leaves in spring, and whitish blotches on otherwise normal green leaves in summer.

The new variety was derived from a periclinal chimera mutant, which itself was derived from a sectorial mutant, which was produced in turn by subjecting rooted cuttings of the parent Forsythia intermedia "Lynwood Gold" (a sport of F. intermedia "Spectabilis") to irradiation with 1,200 rad fast neutrons.

In 1968, three hundred cuttings of "Lynwood Gold" that had been potted and held in cold storage (38° F.) for six weeks and then returned to the greenhouse for two days were irradiated with 1200 rad fast neutrons. One of the plants of this group that broke dormancy formed a shoot with variegated foliage. This plant was cut back repeatedly to induce branching and eventually formed shoots that exhibited different characteristics. Each shoot was propagated by stem cuttings over 10 vegetative generations of selection and propagation. From this plant population two vegetatively selected types and three seedlings were selected. Further propagation and testing of these selections over several more years were shown to be the stable and new forsythia varieties that are the subject of this and four other co-pending plant patent applications; viz:

    ______________________________________                                         Ser. No.   Name          Type                                                  ______________________________________                                         272,063    "Lemon-Screen"                                                                               vegetative selection                                  273,489    "Tinkle Bells"                                                                               vegetative selection                                  271,919    "Minikin"     seedling                                              271,665    "Fairy Land"  seedling                                              271,666    "Pygmy-Red"   seedling                                              ______________________________________                                    

Each differs greatly from the parent "Lynwood Gold" and also from one another.

"Lemon-Screen" was selected from a series of chimeral plants because of its distinct foliage, upright growth habit, and vigor. Cuttings from this plant have been rooted in soil and asexually propagated, and its progeny have displayed homogeneous and stable characteristics.

Throughout this specification, color names beginning with a small letter signify that the name of the color as used in common speech are aptly descriptive. Color names beginning with a capital letter designate values based on the R.H.S. Colour Chart, published by The Royal Horticultural Society of London, England.

The accompanying drawings illustrate the new variety in color as grown in Knox County within the State of Tennessee.

FIG. 1 illustrates 51/2 year old "Lemon-Screen" in bloom in March-April.

FIG. 2 is a close-up view of the flowers.

FIG. 3 illustrates the "Lemon-Screen" plant in leaf.

FIG. 4 is a closer view of the foliage shown in FIG. 3.

The following characteristics distinguish "Lemon-Screen" from its parent and other Forsythia cultivars:

THE PLANT

The "Lemon-Screen" plant form is tall and vigorous, with an upright, fan-shaped habit. "Lemon-Screen" ultimately reaches up to 10 ft. in height. The "Lemon-Screen" shrub is naturally open and graceful but is easily pruned as a tall, flowering screen in spring; it is hardy in Zone 6b or lower. Because of its vigor, "Lemon-Screen" is conveniently produced in the nursery field, but small plants can be grown in containers for a year if cut back substantially. The cultivar is particularly suited for landscape purposes, especially as a tall barrier or visual screen. "Lemon-Screen" will branch out quickly when vegetative shoots are pruned back, making the plant suitable in traffic or crash barriers, where dense plantings are used.

Its parent, "Lynwood Gold", by contrast is tall and slender--a straight upright variety with erect stems and which attains a height of 6 ft. to 71/2 ft. at maturity.

FLOWER

"Lemon-Screen" has light lemon yellow flowers (Yellow 6C) that are 11/2 in. to 13/4 in. in diameter. The internodes are 1" to 2" long on flowering wood. Flowering is early and profuse, with four and up to eight flowers per node on some portions of some stems. The corolla lobes are somewhat reflexed. Flowers have four petals and are sometimes fasciated. The flowers have aborted stamens and/or pistils; consequently, "Lemon-Screen" possesses a high degree of sterility.

The "Lynwood Gold" parent is fertile and has pistils that extend well above its pollen sacs, is late flowering and its medium sized flowers (about 1" to 11/2" in diameter) are almost evenly spaced on the stem. The flowers of "Lynwood Gold" are brilliant yellow (lighter than its parent, F. Spectabilis). The corolla lobes of "Lynwood Gold" are reflexed and its petals are elliptic.

SHOOTS

The mature shoots of "Lemon-Screen" are yellow and pith is slightly lamellate between nodes.

The stems of the "Lynwood Gold" parent are green when young and brown when mature; they are a bit stiff; the pith at the nodes is lamellate, and on one year shoots, the stems between nodes are hollow.

FOLIAGE

The "Lemon-Screen" leaves are simple, serrate, acuminate at the tip, and attenuate at the base. The size of the leaves is not a distinguishing characteristic. The "Lemon-Screen" leaves which appear in the spring are chartreuse or of about a Yellow-Green 151 B color. In the summer the mature leaves are in the Yellow-Green 144 A/C range and have a Yellow-White 158 A, irregular blotch with no defined edge covering about 25-30% of the leaf surface and that extends outward from the mid rib and veins and contrasts with the green colored portions of the leaf. Fall foliage is Greyed Purple 156B. The summer foliage is disease and insect resistant. The young chartreuse leaves which appear after flowering are striking and suggest the plants are in bloom again. Summer pruning leads to the appearance of shoots with leaves that are chartreuse when young.

The leaves of the "Lynwood Gold" parent, on the other hand, are ovate lanceolate in shape and about 3" to 41/2" long and about 1" to 11/2" wide. Both young and old leaves are deep green in color.

To facilitate the comparison of the characteristics and features of "Lemon-Screen", the subject of this application, and its parent, "Lynwood Gold" and also with the four other new mutant offspring varieties of "Lynwood Gold" referred to above, there are attached hereto as Tables 1-5 comparative tabulations of the characteristics and properties of parent and its five offspring mutants that were developed from a single irradiated plant of "Lynwood Gold." Table 1 compares "Lemon-Screen" and its parent "Lynwood Gold". Table 2 compares "Lemon-Screen" and "Pygmy-Red". Table 3 compares "Lemon-Screen" and "Tinkle Bells". Table 4 compares "Lemon-Screen" and "Minikin". Table 5 compares "Lemon-Screen" and "Fairy Land".

                  TABLE 1                                                          ______________________________________                                                      Ser. No. 272,063                                                               LEMON SCREEN                                                      ______________________________________                                         Plant:                                                                         Habit        Tall, open and graceful; Upright,                                              fan shape; vigorous; open                                                      foliage                                                           Size, height up to 10'                                                         Size, width  Hardy Zone 6b (or lower)                                          Vigor        Vigorous                                                          Hardiness                                                                      Productivity Abundant Flowers/highly sterile/                                               pruned wood branches quickly                                      Stems or Shoots:                                                               Color (young)                                                                  Color (mature)                                                                              Yellow                                                            Rigidity     Slightly lamellate between nodes                                  Leaves:                                                                        Type         Simple                                                            Color:                                                                         (young)      Yellow green 151 B or Chartreuse                                               (appear after flowering)                                          (mature)     Normal green (Yellow-Green 144)                                                whitish blotches                                                  (fall)       Greyed Purple 187 B                                               Shape                                                                          tip          Accuminate                                                        base         Attenuate                                                         margins      Serrate                                                           Size                                                                           length       Not distinguishing                                                width        Not distinguishing                                                Venation     Pinnate                                                           Flower:                                                                        Date of Flowering                                                                           Early                                                             Size: width  11/2"-13/4"                                                       Color:       Yellow (6 C)                                                      Corolla:                                                                       length                                                                         lobes        Somewhat reflexed                                                 Petals: number                                                                              4, sometimes fasciated                                            Pistils:     aborted stamens &/or pistils                                      Number per node:                                                                            4 to 8                                                            Insertion angle                                                                on upright stems:                                                              Internodes:  1" to 2" long on flowering wood                                   Stress Resistance:                                                                          Summer foliage disease & insect                                                resistant                                                         Utility Aspects:                                                                            Summer pruning leads to shoot                                                  with chartreuse leaves (young)                                    ______________________________________                                                      LYNWOOD GOLD                                                      ______________________________________                                         Plant:                                                                         Habit        Tall, slender-Upright                                                          straight & erect stems                                            Size, height 6'-71/2'                                                          Size, width                                                                    Vigor                                                                          Hardiness                                                                      Productivity Fertile                                                           Stems or Shoots:                                                               Color (young)                                                                               Green                                                             Color (mature)                                                                              Brown                                                             Rigidity     A bit stiff; pith nodes lamellate;                                             hollow between nodes on one year shoots                           Leaves:                                                                        Type                                                                           Color:                                                                         (young)      Deep Green                                                        (mature)     Deep Green                                                        (fall)                                                                         Shape        ovate lanceolate                                                  tip                                                                            base                                                                           margins                                                                        Size                                                                           length       3-41/2"                                                           width        1-11/2"                                                           Venation                                                                       Flower:                                                                        Date of Flowering                                                                           Late                                                              Size: width  1"-11/2" (medium)                                                 Color:       Brillant Yellow (lighter than its                                              paren Spectabilis)                                                Corolla:                                                                       length                                                                         lobes        Reflexed                                                          Petals: number                                                                              Large, broad, open                                                             Elliptic                                                          Pistils:     Extend well above pollen                                                       sacs (anthers) of stamens                                         Number per node:                                                               Insertion angle                                                                on upright stems:                                                              Internodes:  Flowers almost evenly spaced                                                   on stems                                                          Stress Resistance:                                                             Utility Aspects:                                                               ______________________________________                                    

                  TABLE 2                                                          ______________________________________                                                        Ser. No. 272,063                                                               LEMON SCREEN                                                    ______________________________________                                         Plant:                                                                         Habit          Tall, open and graceful; Upright,                                              fan shape; vigorous; open                                                      foliage                                                         Size, height   up to 10'                                                       Size, width    Hardy Zone 6b (or lower)                                        Vigor          Vigorous                                                        Hardiness                                                                      Productivity   Abundant Flowers/highly sterile/                                               pruned wood branches quickly                                    Stems or Shoots:                                                               Color (young)                                                                  Color (mature) Yellow                                                          Rigidity       Slightly lamellate between nodes                                Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Yellow green 151 B or Chartreuse                                               (appear after flowering)                                        (mature)       Normal green (Yellow-Green 144)                                                whitish blotches                                                (fall)         Greyed Purple 187 B                                             Shape                                                                          tip            Accuminate                                                      base           Attenuate                                                       margins        Serrate                                                         Size                                                                           length         Not distinguishing                                              width          Not distinguishing                                              Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Early                                                           Size: width    11/2"-13/4"                                                     Color:         Yellow (6 C)                                                    Corolla:                                                                       length                                                                         lobes          Somewhat reflexed                                               Petals: number 4, sometimes fasciated                                          Pistils:       aborted stamens &/or pistils                                    Number per node:                                                                              4 to 8                                                          Insertion angle                                                                on upright stems:                                                              Internodes:    1" to 2" long on flowering wood                                 Stress Resistance:                                                                            Summer foliage disease & insect                                                resistant                                                       Utility Aspects:                                                                              Summer pruning leads to shoot                                                  with chartreuse leaves (young)                                  ______________________________________                                                        Ser. No. 271,666                                                               PYGMY RED                                                       ______________________________________                                         Plant:                                                                         Habit          Low, loose graceful                                                            arching to ground                                               Size, height   31/2'-41/2'                                                     Size, width    5'-6'                                                           Vigor          Good vigor                                                      Hardiness      Hardy Zone 6b (or lower)                                        Productivity   Readily roots where branches                                                   touch ground few seed pods                                      Stems or Shoots:                                                               Color (young)  High anthocyanin                                                Color (mature) Purple Red (59 A)                                               Rigidity       Flexible lamellate between nodes                                Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Dark Green                                                      (mature)       Dark Green                                                      (fall)         Anthocyanin (maroon) expressed                                                 in full sun                                                     Shape          Lanceolate (few lobed                                                          leaves on vegetative shoots)                                    tip            Accuminate                                                      base           Attenuate                                                       margins        Serrate                                                         Size                                                                           length         2"-21/2" on flowering wood;                                                    to 23/4" on vegatative wood                                     width          0.3"-0.4" on flowering wood;                                                   to 1" on vegetative wood                                        Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Intermediate                                                    Size: width    11/4"-11/2"                                                     Color:         Yellow (7A)                                                     Corolla:                                                                       length                                                                         lobes          Narrow                                                          Petals: number 4 - sometimes 5                                                 Pistils:       Extend 2/25"-3/25" above                                                       pollen sacs of stamens                                          Number per node:                                                                              2                                                               Insertion angle                                                                on upright stems:                                                              Internodes:    1"-11/2" (11/2" even on                                                        fast growing shoots                                             Stress Resistance:                                                                            disease and insect                                              Utility Aspects:                                                               ______________________________________                                    

                  TABLE 3                                                          ______________________________________                                                        Ser. No. 272,063                                                               LEMON SCREEN                                                    ______________________________________                                         Plant:                                                                         Habit          Tall, open and graceful; Upright,                                              fan shape; vigorous; open                                                      foliage                                                         Size, height   up to 10'                                                       Size, width    Hardy Zone 6b (or lower)                                        Vigor          Vigorous                                                        Hardiness                                                                      Productivity   Abundant Flowers/highly sterile/                                               pruned wood branches quickly                                    Stems or Shoots:                                                               Color (young)                                                                  Color (mature) Yellow                                                          Rigidity       Slightly lamellate between nodes                                Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Yellow green 151 B or Chartreuse                                               (appear after flowering)                                        (mature)       Normal green (Yellow-Green 144)                                                whitish blotches                                                (fall)         Greyed Purple 187 B                                             Shape                                                                          tip            Accuminate                                                      base           Attenuate                                                       margins        Serrate                                                         Size                                                                           length         Not distinguishing                                              width          Not distinguishing                                              Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Early                                                           Size: width    11/2"-13/4"                                                     Color:         Yellow (6 C)                                                    Corolla:                                                                       length                                                                         lobes          Somewhat reflexed                                               Petals: number 4, sometimes fasciated                                          Pistils:       aborted stamens &/or pistils                                    Number per node:                                                                              4 to 8                                                          Insertion angle                                                                on upright stems:                                                              Internodes:    1" to 2" long on flowering wood                                 Stress Resistance:                                                                            Summer foliage disease & insect                                                resistant                                                       Utility Aspects:                                                                              Summer pruning leads to shoot                                                  with chartreuse leaves (young)                                  ______________________________________                                                        Ser. No. 273,489                                                               TINKLE BELLS                                                    ______________________________________                                         Plant:                                                                         Habit          Semi-dwarf; Upright                                             Size, height   4'-41/2'                                                        Size, width                                                                    Vigor          Medium vigor                                                    Hardiness      Hardy Zone 6b (or lower)                                        Productivity   Does not layer naturally (replicates                                           from stools (no seed pods observed)                             Stems or Shoots:                                                               Color (young)  Yellow Green                                                    Color (mature) Light brown                                                     Rigidity       Sparsely lamellate between                                                     nodes - Rigid                                                   Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Medium Green                                                    (mature)       Medium Green                                                    (fall)         Faded green to yellow                                           Shape          Elliptical                                                      tip            Acute on flower shoots                                                         accuminate on vegetative shoots                                 base                                                                           margins        serrate on upper 1/3 near tip                                   Size                                                                           length         2"-3" (with petiole)                                            width          1/2"                                                            Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Early                                                           Size: width    1/2"-3/4" at 45° angle                                   Color:         Bright Yellow (7 B)                                             Corolla:                                                                       length         1/2" open to 45° angle                                   lobes          not reflexed during prime                                       Petals: number 4; occasionally 5 or 6                                          Pistils:       short: anthers slightly                                                        below stigma portion of pistil                                  Number per node:                                                                              2; often 4 per node                                             Insertion angle                                                                               buds & flowers pendulous                                        on upright stems:                                                              Internodes:    1/2--11/2"                                                      Stress Resistance:                                                                            Disease and insect                                              Utility Aspects:                                                                              Can force flowering suitable                                                   for container culture                                           ______________________________________                                    

                  TABLE 4                                                          ______________________________________                                                     Ser. No. 272,063                                                               LEMON SCREEN                                                       ______________________________________                                         Plant:                                                                         Habit       Tall, open and graceful; Upright,                                              fan shape; vigorous; open                                                      foliage                                                            Size, height                                                                               Up to 10'                                                          Size, width Hardy Zone 6b (or lower)                                           Vigor       Vigorous                                                           Hardiness                                                                      Productivity                                                                               Abundant Flowers/highly sterile/                                               pruned wood branches quickly                                       Stems of Shoots:                                                               Color (young)                                                                  Color (mature)                                                                             Yellow                                                             Rigidity    Slightly lamellate between nodes                                   Leaves:                                                                        Type        Simple                                                             Color:                                                                         (young)     Yellow green 151 B or Chartreuse                                               (appear after flowering)                                           (mature)    Normal green (Yellow-Green 144)                                                whitish blotches                                                   (fall)      Greyed Purple 187 B                                                Shape                                                                          tip         Accuminate                                                         base        Attenuate                                                          margins     Serrate                                                            Size                                                                           length      Not distinguishing                                                 width       Not distinguishing                                                 Venation    Pinnate                                                            Flower:                                                                        Date of Flowering                                                                          Early                                                              Size: width 11/2"-13/4"                                                        Color:      Yellow (6 C)                                                       Corolla:                                                                       length                                                                         lobes       Somewhat reflexed                                                  Petals: number                                                                             4, sometimes fasciated                                             Pistils:    aborted stamens &/or pistils                                       Number per node:                                                                           4 to 8                                                             Insertion angle                                                                on upright stems:                                                              Internodes: 1" to 2" long on flowering wood                                    Stress Resistance:                                                                         Summer foliage disease & insect                                                resistant                                                          Utility Aspects:                                                                           Summer pruning leads to shoot                                                  with chartreuse leaves (young)                                     ______________________________________                                                     Ser. No. 271,919                                                               MINIKIN                                                            ______________________________________                                         Plant:                                                                         Habit       Small stature, fine textured; small                                            leaves and small stems; densely                                                foliated                                                           Size, height                                                                               2'-21/2'                                                           Size, width 3'-4'                                                              Vigor       Good vigor but slow growth                                         Hardiness   Zone 6b (or lower)                                                             Layers naturally                                                   Productivity                                                                               Abundant seed pods                                                 Stems or Shoots:                                                               Color (young)                                                                              Light green                                                        Color (mature)                                                                             Brownish green                                                                 Ascending strongly                                                 Rigidity    lamellate between nodes                                            Leaves:                                                                        Type        Simple                                                             Color:                                                                         (young)     Bright green to dark green                                         (mature)    Bright green to dark green                                         (fall)      Fading green until leaf drop                                       Shape       Linear                                                             tip         Accuminate                                                         base        Attenuate                                                          margins     Lightly serrate                                                    Size:                                                                          length      On vegetative shoots - 11/2" attached to 1/2"                                  long slender petiole; smaller on flowering                                     shoots                                                             width       On vegetative shoots - 1/4";                                       Venation    Pinnate                                                            Flower:                                                                        Date of Flowering                                                                          Intermediate                                                       Size: width 1/2"-3/4" (cup shaped) fully reflexed                              Color:      Yellow (9 A)                                                       Corolla:                                                                       length                                                                         lobes       strongly reflexed, very small                                      Petals: number                                                                             4:- short and recurved                                             Pistils:    Short; 1/25" below pollen                                                      sacs of stamens                                                    Number per node:                                                                           2-4                                                                Insertion angle                                                                on upright stems:                                                              Internodes: Short (Flowering shoots 1/4"-3/4"                                              Vegetative shoots up to 2")                                        Stress Resistance:                                                                         Doesn't require same degree of winter prot-                                    tection as most container grown plants of                                      genre                                                              Utility Aspects:                                                                           Blooming can be forced. Especially                                             suited for container culture.                                      ______________________________________                                    

                  TABLE 5                                                          ______________________________________                                                        Ser. No. 272,063                                                               LEMON SCREEN                                                    ______________________________________                                         Plant:                                                                         Habit          Tall, open and graceful; Upright,                                              fan shape; vigorous; open                                                      foliage                                                         Size, height   Up to 10'                                                       Size, width    Hardy Zone 6b (or lower)                                        Vigor          Vigorous                                                        Hardiness                                                                      Productivity   Abundant Flowers/highly sterile/                                               pruned wood branches quickly                                    Stems of Shoots:                                                               Color (young)                                                                  Color (mature) Yellow                                                          Rigidity       Slightly lamellate between nodes                                Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Yellow green 151 B or Chartreuse                                               (appear after flowering)                                        (mature)       Normal green (Yellow-Green 144)                                                whitish blotches                                                (fall)         Greyed Purple 187 B                                             Shape                                                                          tip            Accuminate                                                      base           Attenuate                                                       margins        Serrate                                                         Size                                                                           length         Not distinguishing                                              width          Not distinguishing                                              Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Early                                                           Size: width    11/2"-13/4"                                                     Color:         Yellow (6 C)                                                    Corolla:                                                                       length                                                                         lobes          Somewhat reflexed                                               Petals: number 4, sometimes fasciated                                          Pistils:       aborted stamens &/or pistils                                    Number per node:                                                                              4 to 8                                                          Insertion angle                                                                on upright stems:                                                              Internodes:    1" to 2" long on flowering wood                                 Stress Resistance:                                                                            Summer foliage disease & insect                                                resistant                                                       Utility Aspects:                                                                              Summer pruning leads to shoot                                                  with chartreuse leaves (young)                                  ______________________________________                                                        Ser. No. 271,665                                                               FAIRY LAND                                                      ______________________________________                                         Plant:                                                                         Habit          Small overal & fine textured:                                                  Closely spaced flowers & leaves                                                Dense (young) foliage                                           Size, height   3'-4'                                                           Size, width    5'-6'                                                           Vigor          Good vigor for size                                             Hardiness      Zone 6b (or lower)                                              Productivity   Few seed pods                                                   Stems or Shoots:                                                               Color (young)  Light green                                                     Color (mature) Brownish green                                                  Rigidity       Very flexible lamellate between                                                nodes                                                           Leaves:                                                                        Type           Simple                                                          Color:                                                                         (young)        Medium green (fairly light)                                     (mature)       Medium green (fairly light)                                     (fall)         Mostly faded yellow                                             Shape          Lanceolate                                                      tip            Accuminate                                                      base           Attenuate                                                                      On flowering wood; entire                                       margins        On vegetative wood: serrate top 1/3                             Size:                                                                          length         On flowering wood: - 11/2"-21/2"                                               On vegetative shoots: about 3"                                  width          On flowering wood: 0.2"-0.4"                                                   On vegetative shoots 0.5-0.6"                                   Venation       Pinnate                                                         Flower:                                                                        Date of Flowering                                                                             Intermediate                                                    Size: width    3/4"-11/4"                                                      Color:         Yellow (6 A)                                                    Corolla:                                                                       length                                                                         lobes          Reflexed, small                                                 Petals: number Generally 4-many have 5, 6, 7 and                                              8 on single corolla                                             Pistils:       Extend 3/25" to 4/25" above pollen                                             sacs (anthers) of the stamen                                    Number per node:                                                                              2-4                                                             Insertion angle                                                                on upright stems:                                                              Internodes:    1/4" to about 1"                                                Stress Resistance:                                                             Utility Aspects:                                                                              Very well suited for                                                           container culture.                                              ______________________________________                                     

What is claimed is:
 1. A new and distinct cultivar of Forsythia intermedia named `Lemon-Screen` substantially as shown and described herein. 